What are known above all are pressure oil filters in the oil circuit of internal combustion engines. Said pressure oil filters are connected downstream of the engine oil pump and are attached, usually so as to be exchangeable, to the engine housing or to the cylinder head. The conventional oil filters are afflicted with the disadvantage that they take up a relatively large amount of installation space, in particular because it must be ensured that they are accessible for servicing.
Pressure oil filters are often attached to an adapter, which necessitates further installation space and entails additional costs. In general, long oil lines lead to the adaptation points, which oil lines must usually be drilled, which can entail high costs and also an additional risk of contamination as a result of drilling residues in the engine block and cylinder head.
Virtually all pressure oil filters are arranged in the partial flow of the pump, such that contaminated oil is purified only gradually (partial flow principle).
To keep the filter element free from high oil pressures in particular in cold operating states of the engine or of the internal combustion engine, pressure oil filters generally contain a bypass valve, such that unfiltered oil is initially supplied to the engine lubricating points at low oil temperatures. Such an arrangement is complex and entails additional costs.
DE 197 35 444 A1 discloses an oil filter insert for oil pans of engines and transmissions with integrated suction oil filtration and pressure oil filtration, wherein a filter unit for suction filtration and a filter unit for pressure filtration of engine or transmission oils is arranged on a seal carrier frame. The oil filter insert described in DE 197 35 444 A1 is duly described as being suitable for engine oil filtration but is designed and can be used only for transmission oil filtration of automatic transmissions, in particular because significantly larger engine oil volume flows are circulated in engine oil circuits of internal combustion engines.